Listeria monocytogenes is a facultative intracellular gram positive bacterium. In the genus Listeria, only L. monocytogenes and L. ivanovii are pathogens for human and animals. L. monocytogenes is increasingly recognized as responsible for severe infections in both animals and humans. Pregnant women, new-born and immunocompromised patients are especially susceptible to infection.
To avoid human infection, food sources have, routinely been screened for the presence of Listeria organisms. Potential food sources infected with any species of Listeria have routinely been discarded to avoid infecting the consumer because of the time and expense involved in determining whether the infecting organisms are or are not pathogenic. Thus, there is a need for a means identifying and distinguishing pathogenic Listeria.
In addition, another need has arisen for means to distinguish readily and efficiently between pathogenic and non-pathogenic Listeria species. This information is necessary to determine the course of treatment of suspected listeria infections and for the development of data for epidemiological studies.
The present inventors have developed a DNA probe capable of distinguishing pathogenic Listeria species from non-pathogenic Listeria species. These probes and their uses are described more fully below.